


Apatite

by jaysan



Series: Skelegems AU [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Fusion, Alternate Universe - Steven Universe Fusion, Alternate Universe - Swapfell (Undertale), Fluff, Gem Fusion, Gender-Neutral Pronouns, Other, Other Additional Tags to Be Added, Reader-Insert, Steven Universe References, Swapfell Sans (Undertale), Tooth-Rotting Fluff
Language: English
Status: In-Progress
Published: 2019-12-15
Updated: 2019-12-14
Packaged: 2021-02-24 17:07:22
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,153
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21801433
Author URL: https://archiveofourown.org/users/jaysan/pseuds/jaysan
Summary: The first time Crazy Lace Agate Sans fuses with his Sea Glass.
Relationships: Sans (Undertale)/Reader
Series: Skelegems AU [2]
Series URL: https://archiveofourown.org/series/1572922
Comments: 2
Kudos: 61





	Apatite

**Author's Note:**

  * For [popatochisp](https://archiveofourown.org/users/popatochisp/gifts).
  * Inspired by [Dirty Laundry](https://archiveofourown.org/works/18528973) by [popatochisp](https://archiveofourown.org/users/popatochisp/pseuds/popatochisp). 



> this was inspired by popatochisp's skelegem au on her tumblr, and also her Swapfell Sans and Papyrus/Reader fic Dirty Laundry. (no it's not foncest).

The first time they fused, it was a complete accident.

***

He was so tired.

His quartzes were testing his patience, more so then usual. It was at times like this he felt like a glorified babysitter, rather than the terrifying Crazy Lace Agate he was.

The idiots got it in their mind to have a prank war. That meant, unfortunately for him, and anyone who dared enter his sector, they were prime targets. 

Now, Sans wasn't a total stick in the mud. He could appreciate and make a joke or two (much to the annoyance of his brother). But in just the last few cycles, 6 of his Amethysts and managed to crack themselves. Hairline fractures, but _still_.

Not only that, they'd somehow poof a group of zircon (scared them out of their physical forms with whoopy cushions), annoying 4 peridots into asking for transfers, convinced a few rubies that his Sea Glass could see the future (no, he wasn't laughing at that, you can't prove anything), and scared the daylights out of a sea glass that was passing by with her sapphire.

He was to his eye sockets in reports and complaints, and he was sick of it. He was to tje point where if he got one more complaint, he was going to poof _himself_ , and refuse to reform until at _least_ Era 7, out of pure frustration and exhaustion. 

He cursed the day his brother brought back that 'Home Alone' video for his quartzes to watch. He had half a mind to ban his stupid souvenirs all together, just to have some peace of mind...

... But his Sea Glass was so fond of the trinkets Papyrus brought back for them from his visits to Earth. So, obviously, Sans had absolutely no other choice but to allow the trips.

He'd just have to live with the consequences.

*****

Thankfully, he had his Sea Glass to look forward to.

They were always there for him. Ready give him reassurances when needed, or even a good kick in the coccyx, if necessary. Sometimes, they'd lend an ear to his venting. 

-("No hun, you got it all wrong. Your height makes you all the more terrifying. Closer to hell, as the Earthlings say."

"YOU NEED TO STOP SPENDING SO MUCH TIME WITH MY BROTHER.")-

The two of them were back in his private chambers. Today, their Agate needed to just to forget about the past few weeks. To unwind before his gem cracked under the stress that was rambunctious quartzes. And they were ready to help. Anything for their Agate.

They were making a spectacle of themself, trying to help him unwind with horrid impressions and jokes. Dead set on hearing his ~~beautiful~~ laugh once again. They were mimicking one of his Amethysts, their voice low and so very off. She was the ringleader of the prank group, X7MN9 was her cut, if he remembered correctly. It got a giggle out of him that he would deny to his final breath.

They immediately brightened at the noise. If he was relaxed enough to giggle, they were making progress!

They made their way onto one of the lower support beams, balancing with ease, doing an awful impression of him telling an Amethyst to "CUT IT OUT BEFORE I CUT IT FOR YOU," to tease out more or of that rare sound. Their voice comically low and gruff, not suiting them at all, complete with a mock of his scythe. But it had the desired effect of making him snort in a short, undignified laugh, that they would treasure forever.

_They didn't know he could snort with no nose._

Normally, he'd be concerned about the height they were at. Sea Glasses were so fragile...

A normal gem wouldn't even be bruise, much less poof from that height. They'd be no worse for wear, with the only injury being their ego.

But his Sea Glass proved to him time and time again how painfully aware they were of their own mortality. They were always careful, even when performing dangerous and ridiculous performances for a crowd. They were _always, always, **always**_ careful. No matter what. It was for that reason he didn't worry for the moment, just enjoyed their presence.

Later on, they weren't able to say what cause their mistake. Perhaps they were distracted by him. Their Agate was pretty much always stressed, it came with the job. But they couldn't recall him looking so tired, his gem just a bit more lackluster then they were comfortable with. They're strong, capable, confident Agate looking so... not put together unnerved them so deeply. (They were going to have to talk to the Amethysts to tone it down before they lost their temper. Their Agate's job was hard enough on it's own, and they would not have someone dulling his glow for a few laughs)

Yes, maybe that's what it was. They weren't paying attention, because...

 _They were failing_.

He moved instantly, launching himself across the room, catching them mid fall. They didn't even complete the thought that they could have shattered, _**they**_ _**never got to tell him how they felt -**_

"Are You Hurt?" his voice was the quietest they'd ever heard it in all their time with him. In a tone they'd never heard either: frantic and worried.

 _They were so fragile, and it was his fault, he could have lost them, they were his and he needed to look after them, he was sloppy, sloppy, sloppy, they could have_ _**shattered -** _

They let out a broken sob and he could have sworn he felt his cracked his gem at the noise.

It was their fault, how could they be so careless? _They wanted to help him relax, but they ruined that, they just want him to be_ _ **okay -**_

Neither could say who started glowing. One moment they were clutching each other, embrace desperate for the other to just be okay, the next...

The next, they were one. They... He? She? Felt... safe. **_~~Loved~~._**

They had four arms? Why did they have four arms??

What even were they? A Sea Glass and an Agate???

_No, wait. They knew the answer, didn't they...?_

"... **Apatite**."

It was the sound of their voice, echoing and separate , yet somehow together, that broke them apart, in a shimmering purple and gold cloud.

"I - I DIDN'T MEAN -"

"I'm so sorry, i didn't-"

The pair laid across from one another. Both let out a shaky laugh. Completely overwhelmed and confused by the experience.

Neither was a stranger to fusion. Sea Glasses often fused with one another to put on grand shows for the gems they belonged to and their guests. Sans himself fused often with his brother, and sometimes with a quartz on the battlefield.

But never have either of them lost themselves so entirely in something... something so full of ~~**_love_**~~ an unnamed emotion and -

"... THAT CANNOT HAPPEN AGAIN."

"... Agreed."

*****

It happened again, not month later.

**Author's Note:**

> this is my very first piece of fan content ever, and its a fanfic of an au of someone else au. lol. please go check her out https://popatochisssp.tumblr.com


End file.
